/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.sun.org.apache.xml.internal.security.utils.resolver.implementations;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.net.MalformedURLException;
import java.net.Proxy;
import java.net.URISyntaxException;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;

import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;
import com.sun.org.apache.xml.internal.security.utils.Base64;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverContext;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverSpi;

/**
 * A simple ResourceResolver for HTTP requests. This class handles only 'pure'
 * HTTP URIs which means without a fragment. The Fragment handling is done by the
 * {@link ResolverFragment} class.
 * <BR>
 * If the user has a corporate HTTP proxy which is to be used, the usage can be
 * switched on by setting properties for the resolver:
 * <PRE>
 * resourceResolver.setProperty("http.proxy.host", "proxy.company.com");
 * resourceResolver.setProperty("http.proxy.port", "8080");
 *
 * // if we need a password for the proxy
 * resourceResolver.setProperty("http.proxy.username", "proxyuser3");
 * resourceResolver.setProperty("http.proxy.password", "secretca");
 * </PRE>
 *
 * @see <A HREF="http://www.javaworld.com/javaworld/javatips/jw-javatip42_p.html">Java Tip 42: Write
 * Java apps that work with proxy-based firewalls</A>
 * @see <A HREF="https://docs.oracle.com/javase/1.4.2/docs/guide/net/properties.html">SUN J2SE docs
 * for network properties</A>
 * @see <A HREF="http://metalab.unc.edu/javafaq/javafaq.html#proxy">The JAVA FAQ Question 9.5: How
 * do I make Java work with a proxy server?</A>
 */
public class ResolverDirectHTTP extends ResourceResolverSpi {

  /**
   * {@link org.apache.commons.logging} logging facility
   */
  private static java.util.logging.Logger log =
      java.util.logging.Logger.getLogger(ResolverDirectHTTP.class.getName());

  /**
   * Field properties[]
   */
  private static final String properties[] = {
      "http.proxy.host", "http.proxy.port",
      "http.proxy.username", "http.proxy.password",
      "http.basic.username", "http.basic.password"
  };

  /**
   * Field HttpProxyHost
   */
  private static final int HttpProxyHost = 0;

  /**
   * Field HttpProxyPort
   */
  private static final int HttpProxyPort = 1;

  /**
   * Field HttpProxyUser
   */
  private static final int HttpProxyUser = 2;

  /**
   * Field HttpProxyPass
   */
  private static final int HttpProxyPass = 3;

  /**
   * Field HttpProxyUser
   */
  private static final int HttpBasicUser = 4;

  /**
   * Field HttpProxyPass
   */
  private static final int HttpBasicPass = 5;

  @Override
  public boolean engineIsThreadSafe() {
    return true;
  }

  /**
   * Method resolve
   *
   * @return $todo$ calculate the correct URI from the attribute and the baseURI
   */
  @Override
  public XMLSignatureInput engineResolveURI(ResourceResolverContext context)
      throws ResourceResolverException {
    try {

      // calculate new URI
      URI uriNew = getNewURI(context.uriToResolve, context.baseUri);
      URL url = uriNew.toURL();
      URLConnection urlConnection;
      urlConnection = openConnection(url);

      // check if Basic authentication is required
      String auth = urlConnection.getHeaderField("WWW-Authenticate");

      if (auth != null && auth.startsWith("Basic")) {
        // do http basic authentication
        String user =
            engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpBasicUser]);
        String pass =
            engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpBasicPass]);

        if ((user != null) && (pass != null)) {
          urlConnection = openConnection(url);

          String password = user + ":" + pass;
          String encodedPassword = Base64.encode(password.getBytes("ISO-8859-1"));

          // set authentication property in the http header
          urlConnection.setRequestProperty("Authorization",
              "Basic " + encodedPassword);
        }
      }

      String mimeType = urlConnection.getHeaderField("Content-Type");
      InputStream inputStream = urlConnection.getInputStream();
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      byte buf[] = new byte[4096];
      int read = 0;
      int summarized = 0;

      while ((read = inputStream.read(buf)) >= 0) {
        baos.write(buf, 0, read);
        summarized += read;
      }

      if (log.isLoggable(java.util.logging.Level.FINE)) {
        log.log(java.util.logging.Level.FINE,
            "Fetched " + summarized + " bytes from URI " + uriNew.toString());
      }

      XMLSignatureInput result = new XMLSignatureInput(baos.toByteArray());

      result.setSourceURI(uriNew.toString());
      result.setMIMEType(mimeType);

      return result;
    } catch (URISyntaxException ex) {
      throw new ResourceResolverException("generic.EmptyMessage", ex, context.attr,
          context.baseUri);
    } catch (MalformedURLException ex) {
      throw new ResourceResolverException("generic.EmptyMessage", ex, context.attr,
          context.baseUri);
    } catch (IOException ex) {
      throw new ResourceResolverException("generic.EmptyMessage", ex, context.attr,
          context.baseUri);
    } catch (IllegalArgumentException e) {
      throw new ResourceResolverException("generic.EmptyMessage", e, context.attr, context.baseUri);
    }
  }

  private URLConnection openConnection(URL url) throws IOException {

    String proxyHostProp =
        engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpProxyHost]);
    String proxyPortProp =
        engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpProxyPort]);
    String proxyUser =
        engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpProxyUser]);
    String proxyPass =
        engineGetProperty(ResolverDirectHTTP.properties[ResolverDirectHTTP.HttpProxyPass]);

    Proxy proxy = null;
    if ((proxyHostProp != null) && (proxyPortProp != null)) {
      int port = Integer.parseInt(proxyPortProp);
      proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHostProp, port));
    }

    URLConnection urlConnection;
    if (proxy != null) {
      urlConnection = url.openConnection(proxy);

      if ((proxyUser != null) && (proxyPass != null)) {
        String password = proxyUser + ":" + proxyPass;
        String authString = "Basic " + Base64.encode(password.getBytes("ISO-8859-1"));

        urlConnection.setRequestProperty("Proxy-Authorization", authString);
      }
    } else {
      urlConnection = url.openConnection();
    }

    return urlConnection;
  }

  /**
   * We resolve http URIs <I>without</I> fragment...
   *
   * @return true if can be resolved
   */
  public boolean engineCanResolveURI(ResourceResolverContext context) {
    if (context.uriToResolve == null) {
      if (log.isLoggable(java.util.logging.Level.FINE)) {
        log.log(java.util.logging.Level.FINE, "quick fail, uri == null");
      }
      return false;
    }

    if (context.uriToResolve.equals("") || (context.uriToResolve.charAt(0) == '#')) {
      if (log.isLoggable(java.util.logging.Level.FINE)) {
        log.log(java.util.logging.Level.FINE, "quick fail for empty URIs and local ones");
      }
      return false;
    }

    if (log.isLoggable(java.util.logging.Level.FINE)) {
      log.log(java.util.logging.Level.FINE,
          "I was asked whether I can resolve " + context.uriToResolve);
    }

    if (context.uriToResolve.startsWith("http:") ||
        (context.baseUri != null && context.baseUri.startsWith("http:"))) {
      if (log.isLoggable(java.util.logging.Level.FINE)) {
        log.log(java.util.logging.Level.FINE, "I state that I can resolve " + context.uriToResolve);
      }
      return true;
    }

    if (log.isLoggable(java.util.logging.Level.FINE)) {
      log.log(java.util.logging.Level.FINE, "I state that I can't resolve " + context.uriToResolve);
    }

    return false;
  }

  /**
   * @inheritDoc
   */
  public String[] engineGetPropertyKeys() {
    return ResolverDirectHTTP.properties.clone();
  }

  private static URI getNewURI(String uri, String baseURI) throws URISyntaxException {
    URI newUri = null;
    if (baseURI == null || "".equals(baseURI)) {
      newUri = new URI(uri);
    } else {
      newUri = new URI(baseURI).resolve(uri);
    }

    // if the URI contains a fragment, ignore it
    if (newUri.getFragment() != null) {
      URI uriNewNoFrag =
          new URI(newUri.getScheme(), newUri.getSchemeSpecificPart(), null);
      return uriNewNoFrag;
    }
    return newUri;
  }

}
